Liquid addition mixer



Dec. 10, 1968 HSHER ET AL 3,415,494

LIQUID ADDITION MIXER Filed July 13, 1966 2 Sheets-Sheet 1 I NVENTOH $1 CHESTER DONALD FISHER ROBERT L. ST'R 0UP BY WAYNE ZERKEL.

ATTYS,

Dec. c, F|$HER ET AL 3,415,494

LIQUID ADDITION MIXER Filed July 15, 1966 2 Sheets-Sheet 2 92 mvEu'roRs:

CHESTER DONALD FISHER ROBERT L. STROUP M v WAYNE ZERKEL ATTYS,

United States Patent LIQUID ADDITION MIXER Chester Donald Fisher, Muncy, and Robert L. Stroup, Williamsport, Pa., and Wayne Zerkel, Fort Wayne, Ind., assignors to Sprout, Waldron & Company, Inc.,

Muncy, Pa., a corporation of Pennsylvania Filed July 13, 1966, Ser. No. 564,944 5 Claims. (Cl. 259-45) ABSTRACT OF THE DISCLOSURE A liquid addition mixer characterized by a vertical cylindrical casing containing a coaxial rotatable shaft extending therethrough and carrying a plurality of mixing paddles in the lower mixing region of the casing. A downwardly flaring frusto-conical liquid distribution element on the shaft above the mixing paddles is positioned adjacent a port communicating with a bore of the shaft through which a liquid is centrifugally discharged onto the underside of the frusto-conical distribution element. A material inlet is provided at the top of the casing and mixing and distributing blades on the shaft above the distributor element provide a uniform feed of material over the outer surface of the element. The liquid is outwardly directed by centrifugal force in small droplets and is dispersed uniformly into the flow of materials at the lower edge of the liquid distribution element.

The present invention relates generally to liquid addition mixers for blending a liquid additive into a dry particulate material. The invention is particularly adapted for use in feed mills for the addition of a variety of liquids such as molasses, fish liquid, fats, etc. to different types oflivestock feeds.

Feed mill liquid addition mixers are conventionally of a horizontal type wherein one or more rotating agitators serve to advance the feed from one end of the unit to the other while the liquid to be added is simply dripped from a pipe into the agitated material. Due to the horizontal disposition of the mixer and the manner in which the liquid is added, buildup of material on the mixer casing and agitators is substantial and a great deal of time is required for cleaning.

Mixers of the conventional horizontal type are in addition generally adapted for operation at only a single speed. Since diflerent types of feeds and additives require different mixing speeds, the usual feed mill normally includes high speed mixers for difficult to mix materials and low speed mixers for mixing materials containing friable ingredients, these separate mixing units representing a substantial investment.

It is conventional practice in present mixers to introduce the liquid into the interior of the mixer by simply pouring the liquid through a pipe into the upper region of the mixer. In some instances, a pipe is extended along the length of the mixer having spaced holes through which the liquid may pass at different points into the agitated material. Attempts at atomizing the liquid additions for feed mixers have not been satisfactory, primarily because of the fact that the liquid additions are low grade by-product liquids containing various sizes of foreign material which would not pass through a spray orifice. Elaborate filtering devices would be necessary in order to atomize the liquid additions and to date no satisfactory system of this type has been devised.

In view of the above, it can be understood that for most eflicient operation a liquid addition mixer of the type described should be of a design which retains a very small residue of materials in the mixer casing to minimize lost ingredients and the cleaning time required. Since it is impractical to clean a mixer after every change of feed formula, any residue that does remain in the mixer must be of sufficient hardness to remain in the casing until removed during the cleaning step. The liquid should preferably be added in the center of the mixer away from the casing and should preferably be in the form of small droplets to minimize the impingement of the liquid on the case and the buildup of residue thereon. All the parts of the mixer should additionally be readily accessible to permit rapid inspection and cleaning of the unit.

The present invention satisfies all of these requirements by providing a mixer comprising a vertical cylindrical casing into the upper end of which the feed or other loose material is fed. A vertical coaxial shaft driven in rotation by a variable speed drive supports several mixing paddles in apre-mixing region at the upper end of the casing wherein the feed is uniformly blended and distributed around the circumference of the casing. The feed flows downwardly in an annular path around a conical liquid distribution element which is mounted for rotation on the shaft and serves to distribute the liquid in droplet form to the inner side of the feed layer passing t-hereanound. The liquid droplets and feed are then thoroughly mixed by a series of adjustable mixing paddles on the lower end of the shaft, the mixed feed product being discharged through the bottom of the casing.

The vertical design of the mixer and the introduction of the liquid in droplet form in the interior region of the mixer prevents the buildup of undesirably large residues on the casing. The variable speed of the unit combined with the adjustable paddles of the mixer permit use of the unit for both high speed and low speed mixing operation. By hingedly mounting one-half of the cylindrical mixer casing, access to the entire casing is readily provided and cleaning may be accomplished in a very short time.

In view of the above it can be understood to be a first object of the present invention to provide a liquid addition mixer adaptable for operation at selectively variable speeds to suit the characteristics of the mix ingredients.

Another object of the invention is to provide a mixer as described having a novel liquid introduction means which is adapted to introduce the liquid in droplet form at the interior of the mixer and thus permits operation with little residue buildup.

A further object of the invention is to provide a liquid addition mixer as described having improved efficiency and thus requiring relatively low power input.

A still further object is to provide a mixer as described, all parts of which are readily accessible for cleaning and adjustment.

Still another object is to provide a mixer as described of a compact design which may be inexpensively manufactured and maintained.

Additional objects and advantages of the invention will be more readily apparent from the following detailed description of an embodiment thereof when taken together with the accompanying drawings in which:

FIG. 1 is a side elevational view of a .mixer embodying the present invention, the view being partly broken away to more clearly illustrate interior portions of the mixer mechanism;

FIG. 2 is a plan view of the mixer shown in FIG. 1 showing in broken lines the manner in which the hinged section of the casing may be opened for access to the mixer interior;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a sectional View taken along line 44 of FIG. 3 with the hinged section of the casing omitted; and

FIG. is an enlarged sectional view taken along line 5-5 of FIG. 3.

Referring to the drawings, and particularly FIG. 1 thereof, the mixer generally designated embodying the present invention includes a vertical cylindrical casing 12 supported on a suitable box-shaped base 14 within which is mounted the mixer drive as will be presently described. The casing 12 includes a section 12a secured to the base 14 and a section 12b hingedly mounted to the section 12a at 16 in FIG. 2 to permit access to the interior of the casing for cleaning and inspection purposes. A number of latches 18 are provided to secure the casing sections 12a and 12b during operation of the mixer.

The casing 12 includes a bottom plate 20 at the lower end thereof and a spider assembly 22 in the upper region thereof, both of which are secured to the section 12a of the casing. A vertical mixer shaft 24 is coaxially mounted within the casing, passing through the bottom plate 20 and the spider 22 and being journaled by the flanged bearing 26 bolted beneath the bottom plate 20 and the ball bearing assembly 28 in the spider 22. The casing includes a top plate 30 attached to the casing portion 12a, which top plate 30 includes a flanged opening 32 adapted for connection to a feed inlet duct. At the lower end of the casing an outlet duct .34 extends tangentially from casing section 12a and is flanged at 36 to facilitate attachment to an additional duct as required.

Extending radially from the upper end of the mixer shaft 24 is a series of pre-mixing blades 38 in the region 40 above the spider 22 which constitutes a feed pie-mixing and distributing region. Directly below the spider 22 is located a liquid addition means 42 mounted on the shaft 24 and comprising a plurality of radially directed liquid pipes 44 communicating with a hollow bore 46 of the shaft, the bore 46 being in fluid communication at the upper end of the shaft with a liquid inlet pipe 47. Extending from the shaft 24 and overlying the liquid pipes 44 is a frusto-conical liquid distribution element 48 against the inner face 48a of which the liquid is thrown by centrifugal force and from the bottom edge 48b of which liquid is dispersed in droplet form into the particulate flow descending from the pre-mixing and distribution region 40. Attached to the outer face of the element 48 are a plurality of spaced vanes 49 which are adapted to impart a rotary motion to the annular flow of feed passing downwardly over the element 48 from the region 40.

The casing below the liquid addition means 42 comprises a mixing region 50 within which the feed and liquid addition dropping by gravity flow are intimately mixed by the axially and circumferentially spaced mixing paddles 52 which are threadedly mounted in the shaft 24 and extend radially therefrom. The paddles 52 are radially rand angularly adjustable upon release of the securing nuts 54. The lowermost set of mixing paddles, as illustrated in FIG. 3, are provided with tip extension 55 and are vertically rather than angularly adjusted to drive the mixture tangentially through the outlet duct 34.

In FIG. 5 the details of the liquid inlet arrangement at the top of the shaft 24 is clearly illustrated. The inlet pipe 47 is threadedly connected with a shouldered nozzle 56, the lower end 58 of which extends within the hollow pre-mixer hub 60, bearing therein against the bronze plug 62. The pre-mixer hub 60, from which the pre-mixer blades 38 radiate, is mounted over the upper end of the shaft 24 and is secured thereto by set screw 64 seated in the annular slot 66 of the shaft. The shaft bearing assembly 28 in the spider 22 is sealed from the pre-mixing region 40 by the annular seal assembly 68 mounted on the lower end of the pre-mixer hub 60.

The liquid distribution element 48, as shown in FIG. 5, is attached to an annular sleeve 70 seated on the shoulder 72 of the shaft. Rotation of the element 48 with respect to the shaft is prevented by the slotted annular cage 74 through which the pipes 44 are inserted upon assembly of the mixer.

As shown most clearly in FIGS. 1 and 2, a drive support housing 76 extending rearwardly from the fixed section 12a of the casting includes a vertical hinge support member 78 to which the vertical d'rive support plate 80 is pivotally attached by the hinge 82. A variable speed drive unit 84 is bolted to the drive support plate 80 and includes a drive motor 86. The output shaft 88 of the variable speed drive unit 84 extends downwardly into the hollow base 14 and includes a grooved sheave 90 adapted for driving a somewhat larger, similarly grooved sheave 92 on the lower end of the mixer shaft 24 by means of the multiple belt drive 94. The belt drive tension is adjusted by means of the adjustment bolt 95 shown in FIG. 2 which controls the position of the pivotal control plate 80. Suitable drive controls (not shown) are provided to permit appropriate speed variation of the mixer. A removable section 97 of the base 14 includes a ventilator screen 98 to permit a cooling air flow to circulate around the drive belt and sheaves.

In operation, with the variable speed drive rotating the mixer shaft 24 at a preselected speed, loose particulate material such as a feed or feed mixture is introduced into the casing 12 through the flanged opening 32 at the top of the mixer. The feed passes into the pre-mixing and distributing region 40 wherein it is mixed and radially distributed so as to pass in a uniform manner through the openings of the spider 22. The spider 22 includes a downwardly flared hub 100 from which the legs 102 thereof radiate, the shape of the hub 100 guiding the feed material into an annular flow path.

The annular flow of material drops onto the outer conical surface of the liquid distribution element 48 and is directed thereby into an even narrower annular flow path. The vanes 49 at the same time impart a rotary motion to the flow of material so that the feed particles follow a helical path as they pass over the bottom edge 48b of the element 48. The liquid to be added to the feed passes from the liquid inlet 47 through the bore 46 in the shaft 24 and out through the several pipes 44 wherefrom it is thrown by centrifugal force onto the underside 48a of the element 48. The centrifugal force imparted to the liquid by the rotating element moves the liquid outwardly to the lower edge 48b thereof whereupon it is dispersed in droplet form onto the feed passing therearound in an annular flow path. By directing the fine droplets of liquid from the interior of the mixer onto the surrounding feed flow, direct initial contact of the liquid with the casing is avoided and residue buildup is minimized.

Following the dispersion of the dropelts into the feed, the feed and liquid pass into the mixing region 50 wherein they are subjected to the mixing action of the .adjustable paddles 52. The mixing action of the paddles can be varied to suit the feed ingredients by changing the angle and/or the radial projection of the paddles. On reaching the bottom of the casing, the mixed feed is propelled from the casing by the lowermost paddles through the tangentially aligned outlet duct 34.

With the present mixer, due to the reduction of the liquid to small droplets and the rapid dispersion of the liquid droplets into the feed, the relative speed of agitation can be substantially reduced over that necessary with other types of feed mixers. Since, for any given mix, the agitator can be run at a relatively low speed, the power requirement of the unit is greatly reduced with a corresponding reduction in wear on the mixing paddles and casing. Because of the vertical disposition of the casing, there is no loose residue left in the casing after the mixing cycle is completed. All loose residue drops to the bottom of the casing and is discharged by the paddles at the bottom of the mixer.

By means of the variable speed drive, the speed of the mixer can be appropriately set for the ingredients to be processed. A high mixing speed will generally be necessary for finely ground heavier ingredient mixes of the concentrated type which may include molasses or other liquid as an additive. Fibrous light mixes containing flakes and pellets on the other hand would be mixed at a substantially lower speed to preserve the texture of the ingredients. In view of the adaptability of the mixer to high or low speed operation, and due to the fact that there is virtually no buildup of material on the casing or moving parts, the mixer may be successively run on a variety of formulae and it is no longer necessary to have two different types of mixers for high and low speed operation.

The present liquid distributing means is ideally suited for use with low grade by-produt liquids containing foreign materials since it has no small apertures which could become clogged by such liquids. Any foreign matter present passes easily through the bore 46 and pipes 44 onto the element 48 and is distributed into the feed along with the liquid droplets.

Manifestly, changes in details of construction can be effected by those skilled in the art without departing from the spirit and the scope of the invention as defined in and limited solely by the appended claims.

We claim:

1. A liquid addition mixer comprising a vertical cylindrical casing, a vertical shaft mounted coaxially within said casing for rotation therewithin, means for rotating said shaft, material inlet means at the upper end of said casing, a material pre-mixing and distributing region in the upper end of said casing, a plurality of pre-mixing blades radially extendin from the shaft in said pre-mixing and distributing region adapted for pro-mixing materials passing therethrough and distributing the materials around the periphery of said casing, liquid addition means on said shaft below said pre-mixing and distributing region, said liquid addition means comprising means for introducing a liquid into the interior of said shaft, port means in said shaft communicating with said liquid introduction means permitting centrifugal discharge of liquid from said shaft during rotation thereof, a liquid distribution element on the shaft defining a downwardly flaring frusto-conical surface concentrically spaced from the shaft and adapted to receive liquid discharged from said port means thereof, said element being adapted to centrifugally disperse the liquid in droplet form from the lower edge of said frusto-conical surface into a flow of material passing therearound from said pre-mixing and distributing region, a plurality of mixing paddles extending radially from said shaft below said liquid addition means, and means in the lower end of said casing for exhausting mixed material from the mixer.

2. A mixer as claimed in claim 1 including a plurality of vanes on said liquid distribution element adapted to impart rotational movement to the particulate materials passing therearound.

3. The mixer as claimed in claim 1 wherein said means for rotating said shaft comprises variable speed drive means.

4. The mixer as claimed in claim 1 wherein said cylindrical casing includes a hingedly mounted section which may be opened to permit inspection and cleaning of the mixer.

5. A mixer as claimed in claim 1 wherein said mixing paddles may be angularly and radially adjusted to vary the mixing action imparted thereby.

References Cited UNITED STATES PATENTS 1,855,548 4/1932 Forster 259-8 2,146,776 2/1939 Strominger 259-23 2,592,709 4/1952 Kinnaird 259-8 2,953,359 9/1960 Mau 259-23 XR 3,090,606 5/1963 Burnet 259-9 XR 3,227,424 1/1966 Cunningham 259-8 3,245,663 4/1966 Austin 259-8 FOREIGN PATENTS 1,068,670 11/1959 Germany.

WALTER A. SCHEEL, Primary Examiner. J. BELL, Assistant Examiner.

U.S. Cl. X.R. 

